Expanded metals are materials with orifices in the surface, which are produced by offset cuts without loss of material, while performing an expanding deformation at the same time, using flat materials, particularly metal sheets or metal strips.
In this process (with vertical orientation of the machine), the following steps are performed in consecutive cycles: the flat starting material is guided between blades, the starting material is cut by the moving blade while undergoing an expanding deformation, the blade is retracted vertically and then displaced laterally by half a mesh length, the blade is again displaced vertically for cutting into the starting material, thus creating the first meshes, and subsequently the blade is again vertically retracted and displaced laterally in the starting position, whereupon the starting material can again be fed. Thereafter, the expanded metal can be further processed, such as flat-rolled.
The expanded metals produced in this way are generally made of a high number of meshes in the longitudinal and transverse directions. During production, an even vertical cutting depth or immersion depth between the two blades is required since even minor deviations in the lateral direction, which is to say minor expansion differences of the meshes produced in one reciprocating movement, can form distortions in the finished mesh pattern, which are immediately apparent to the observer due to the regularity of the pattern, particularly in the case of larger widths and lengths. This may result in considerable visual impairment of the otherwise very aesthetic expanded metal. In the case of longer expanded metals, these distortions occurring in the longitudinal direction can add up and result in larger warping.
So as to correct and/or adjust the height positions of blades received in blade holding fixtures, at times a rough setting is performed in that cigarette paper or the like is placed between the blade and blade holding fixture. Such settings, however, are imprecise and only allow rough adjustments within discrete values.
U.S. Pat. No. 3,308,597 describes an expanded metal machine having a fixed blade, a displaceable blade, and the displaceable blade being vertically and transversely displaceable with a reciprocating motion in a vertical and a transverse direction, respectively. In that invention, cutting projections are formed both on the upper blade and on the lower blade, the projections engaging each other such that the flat material is received between the cutting projections disposed offset from one another during the cutting movement. Both the upper and the lower blades are displaced periodically in the lateral direction.
DE 197 28 913 C1 discloses an expanded metal machine, wherein for setting the cutting stroke and hence the mesh size of the expanded metal or mesh pattern to be produced a maximum cutting stroke can be reduced by means of adjusting wedges controlled by step motors. The maximum cutting stroke here is defined by eccentric disks provided on upper blade carriers or an upper blade holding fixture, the disks being driven by a shaft and pressing the upper blade carrier downward by means of the adjusting wedges.